During Apple's "awe dropping" event earlier this month, the company unveiled its Hypertension Notifications feature, which is now available on WatchOS 26 devices, including the new Apple Watch Series 11 and Ultra 3. Similar to sleep apnea, noise and heart health notifications on the Apple Watch, Hypertension Notifications aim to alert users of possible hypertension. But then, what do you do with that information?
Below, we discuss everything you should know to help you better understand how Hypertension Notifications work and what to do if you get an alert.
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What is hypertension in the first place?
High blood pressure is also called hypertension, and according to the American Heart Association, it occurs when the "force of your blood pushing against the walls of your blood vessels is too high." Hypertension can lead to serious cardiovascular problems like a stroke or heart attack. Contrary to popular belief, high blood pressure can affect people of all ages -- not just adults.
According to the World Health Organization, 1.3 billion adults across the globe have hypertension. About 46% of adults with hypertension aren't even aware that they have the condition because they may not feel any symptoms. The only way to know if you have hypertension is to get your blood pressure checked.
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How do hypertension notifications work on the Apple Watch?
Apple Watch's optical heart sensor uses photoplethysmography, or PPG, data, which measures blood volume changes through the skin, to analyze how your blood vessels respond to your heartbeats. Working passively, the deep learning algorithm uses 60-second segments of PPG signals as inputs, which are collected about every two hours. This PPG data is also filtered using the Apple Watch's accelerometer data to figure out if the user is sitting still, which is required for the algorithm. It then reviews this data over 30-day periods, and if it notices consistent signs of hypertension, it will alert the user.
Though this feature won't detect all instances of hypertension, Apple expects these alerts to notify over 1 million people of undiagnosed hypertension within the first year of its launch. This is crucial because there are lifestyle changes and medical interventions that can help people control their high blood pressure, preventing more serious issues down the line. Early intervention and treatment are key. Plus, as we mentioned, people can be unaware that they have hypertension because of no noticeable symptoms, so receiving a hypertension alert on their watch allows them to take action they wouldn't have otherwise taken.
What should you do if you get a hypertension notification on your Apple Watch?
If a hypertension notification is received, Apple recommends that you log your blood pressure with a third-party blood pressure cuff for seven days before sharing the results with your doctor.
The hypertension notifications feature isn't intended for use by people under age 22, those who are pregnant or people who have already been diagnosed with hypertension.
The Apple Watch Series 11 on display at Apple's Cupertino event, Sept. 9. Vanessa Hand Orellana/CNET
Are hypertension notifications blood-pressure readings?
Though this new feature can notify you of potential hypertension, it isn't the same as a blood-pressure reading you'd get from a cuff. That's because a smartwatch's optical sensors aren't as accurate as a cuff that can measure the force of your blood on an artery as it tightens and relaxes around your arm. Unlike a cuff, a smartwatch would also require calibration to create a baseline.
How hypertension notifications were created
The hypertension notifications feature was developed using data from multiple studies with over 100,000 participants and advanced machine learning. It was later validated in a clinical study with over 2,000 participants.
When will hypertension notifications be available?
The hypertension notifications feature is available in over 150 countries and regions, including the US and Europe. It can be found on the Apple Watch Series 9 and later, and Apple Watch Ultra 2 and later. However, these devices must operate on WatchOS 26.
When the WatchOS 26 update was released on Sept. 15 for the Apple Watch Series 9, Series 10 and Ultra 2, hypertension notifications was included. The notifications will also be on the Apple Watch Series 11 and Ultra 3, which were released on Sept. 19.
Are hypertension notifications FDA-cleared?
As of Sept. 11, the hypertension notifications feature has been cleared by the US Food and Drug Administration.